1. Field of the Invention
The present invention relates generally to computer aided design (“CAD”). More specifically, the present invention relates to an associative computer aided design methodology.
2. Background Art
The present invention is a new and more-effective methodology for associative computer aided design. “Catia V5” is computer software available from DASSAULT SYSTÈMES, 9, quai Marcel Dassault, BP 310 92156 Suresnes Cedex, France (www.3ds.com). The functionality and operation of Catia V5 is generally known in the computer aided design industry. Catia V5 provides three functions to implement associative computer aided design: (1) “Reference-Reference,” (2) “Reference-Instance,” and (3) “Instance-Instance.” These functions are referred to as “Multi-Model Links” or “MMLs.”
One drawback of the associative computer aided design methodologies provided in Catia V5 is an undesirable phenomena referred to here as “looping.” In one example, looping occurs when Catia MMLs are used in the computer aided design of a multi-component structure that interfaces with itself in some fashion to create a somewhat “continuous” structure. One example of such a structure is a shell or enclosure, such as an automobile. An automobile body comprises a plurality of different components, or component groups, that must collectively (and accurately) fit together in a finished assembly. Assuming that adjacent components in the assembly are associatively linked using one or more Catia MML functions, a change to one component may result in an undesired “loop” or “infinite loop” of all components in the assembly. Other examples of structures vulnerable to the looping phenomena may exist.
Because of the looping problem, some companies simply do not let their computer aided designers use the Catia V5 associative design functions. Other companies use pen-and-paper methods to manage and control associativity among structures vulnerable to looping. One method is the use of one or more “central” spreadsheets by all computer aided designers engineers involved in the design of a structure vulnerable to looping.
While the spreadsheet method may technically be effective at reducing or eliminating the looping phenomena, it is not an automated, efficient or robust solution—especially when there are a large number of designers or structures involved.
The present invention is a method that allows computer aided designers to avail themselves of associative design functionality, such as that provided by Catia V5, while at the same time avoiding the undesirable looping problem associated with the prior art.